Mundus

Mundus the Dark Emperor (lit. "World" in Latin) is the primary antagonist of the first Devil May Cry, and his defeat at the hands of Sparda two millennia ago sets the scene for the series.

History
The little that is revealed about Mundus in the series is that two millennia ago, he was born into the depths of the Demon World, and quickly rose to power. He planned to lead an assault on the Human World, but one of his chief generals, Sparda, "awoke to justice", single-handedly defeated both Mundus and his armies, and sealed the main gate into the Demon World.

At the end of Devil May Cry 3, as Sparda's son Vergil wanders the Demon World, he comes upon Mundus and challenges him. However, he is defeated, and transformed into Nelo Angelo.

In Devil May Cry, Mundus attempts to escape into the Human World by opening a gate on Mallet Island. At the same time, he uses Trish to manipulate Sparda's other son, Dante, into coming to the island so that he can be killed. Though Dante does come to the island, he is able to defeat Mundus and his minions, and Mundus falls back into the Demon World.

In Devil May Cry 3, and during some parts of Devil May Cry, Mundus appears as three glowing orbs arcing with energy, though it is uncertain if this is his true form, or merely an avatar. Mundus also appears as a marble statue of a three-eyed, angelic youth and his long hair, but this form later takes an older, bearded appearance with a big hole in his chest (Probably a scar from his battle against Sparda). During his final battle with Dante, the marble breaks away, revealing a grotesque, writhing being made of lava, with three eyeballs and a mouth attached by stalks to its head.

Mundus appears to have been worshiped by the residents of Mallet Island, as there are many statues to his angelic likeness situated about the castle, and Dante comes across many clues of strange rituals during the game. However, it is also possible that these were instead constructed by the demons Mundus fills the island with.

Background
The mundus Cereris was a pit in Roman mythology which contained an entrance to Hades, the underworld, which was ruled by Pluto, the Roman god of the underworld; Mundus is identified as Pluto twice within Devil May Cry. The stone covering the pit, known as the lapis manalis, would be removed three times a year, and when it was removed it was believed that the spirits of the blessed dead would commune with the living.

Mundus' three eyes are likely a reference to Satan, who is portrayed with three faces in Dante Alighieri's The Divine Comedy. Satan is also considered the "prince of this world" and the "prince of darkness", both titles which Mundus shares with him.

Trivia

 * In the opening cutscene of Devil May Cry 2, a statue resembling Mundus's younger and more angelic form is briefly shown as the narration recounts a portion of the tale of Sparda.